For some time foaming agents have been used to increase the effectiveness of water in the prevention and suppression of fires. Systems have traditionally used foaming agents, commonly known as surfactants, mixed in holding tanks or introduced into the water stream by a variety of methods. More recently systems have been developed which also provide for the injection of compressed air into the water/surfactant mixture to provide an improved quality and volume of foam.
In U.S. Pat. No. 5,582,776 of the present inventors issued Dec. 10, 1996 is disclosed a portable apparatus for generating foam. The apparatus disclosed was particularly directed at an apparatus for making compressed air foam to be used in stationary or portable fire fighting systems and emergency response units. The system is particularly applicable to portable systems used in forestry, structure protection, rural and urban grass fires (Class A fires), and oil and gas fires (Class B fires).
In U.S. Pat. No. 6,733,004 of one of the present inventors issued May 11, 2004 is disclosed a portable apparatus for generating foam where there is provided an improved valve arrangement for controlling the formation of the foam.
The arrangement shown in the above patents was particularly designed as a portable unit for use in remote locations.
It is known that foam systems of this type can act to extinguish fires and also as a fire retardant.
U.S. Pat. No. 6,522,616 (Wallace) issued Feb. 25, 2003 discloses a fire prevention system for a building which has foam nozzles outside the building and on the roof.
U.S. Pat. No. 7,104,334 (Thompson) issued Sep. 12, 2006 discloses a portable remote actuable foam spray system which can be left in place when the persons depart and activated remotely. It shows in FIGS. 7 to 9 a roof mounted nozzle.
U.S. Pat. No. 5,165,482 (Smagac) issued Nov. 24, 1992 discloses a sprinkler system for protecting a building when a fire approaches. It does not use foam.
U.S. Pat. No. 6,450,264 (Christian) issued Sep. 17, 2002 discloses a roof mounted sprinkler system for forest fires. It does not use foam.
U.S. Pat. No. 5,125,458 (Berman) issued Jan. 30, 1992 discloses a sprinkler system for protecting a building when a fire approaches. It does not use foam.